Die Swell
Die swell is the expansion of a polymer melt after it exits an extrusion die. It is caused by elastic recovery of the material and is influenced by molecular weight, chain entanglement, temperature, shear rate, and die geometry.
See related terms:
Extrusion
Melt Flow Index (MFI)
Molecular Weight Distribution
Rheology
Viscosity
Extrusion die schematic showing melt expansion after exiting the die.